This invention relates to a file retrieval apparatus and method for finding a desired file from a plurality of files.
In a general operating system (OS), file management is made such that a user himself/herself generates tree-structured directories and arbitrarily stores a file in a desired directory. In this file management system, the user stores files containing the same subject matter for him/her in one directory as a file group, and makes the directory have hierarchical structure. This helps the user to perform retrieval of files.
In a recent data base system, a user sets a keyword with respect to an object file, and uses the keyword for retrieving the file. In this system, each file has its file name and one or more keywords. The user designates one or plural keywords, which may be included in the object file, in the form of logical operation. A retrieval device displays files corresponding to the logical operation of one or a plurality of keywords. If the object file is in the displayed files, the user designates the object file and thus performs file retrieval.
On the other hand, there exists a retrieval device for retrieval using hierarchical-structured keyword. In this device, keywords have a hierarchical structure by adopting a tree structure, similar to a directory structure of a general OS. The tree-structured keywords are displayed by display means. An operator uses the displayed tree-structured keywords to perform retrieval. Further, the device can edit the hierarchical structure of keywords by providing hierarchical-structure editing means.
In the conventional retrieval device, in a case where retrieval is made by using hierarchical-structured keywords having a structure as shown in FIG. 5, a keyword "car" which is designated by the user is developed into: ##EQU1## Then, files having keywords "car, special-purpose vehicle, ambulance, patrol car, private use car" are displayed as retrieval results.
However, in the conventional file management system in OS, there is only one retrieval path for retrieving a file stored in a storage medium. If a user wants to treat a file with a plurality of aspects, this kind of file management system is inconvenient. That is, within the hierarchical structure generated in accordance with the user's intention, if one file has a plurality of meanings to a user, retrieval of that file should be made from a plural portions of a hierarchical structure. However, in the conventional file management system, such retrieval is impossible.
Further, in recent data-base retrieval using a keyword, a plurality of keywords are added to one file so as to give a plurality of meanings to the file. However, there is a problem that a user cannot form a hierarchical structure of keywords in accordance with his/her intended meanings, and cannot use such hierarchical structure for retrieval.
Furthermore, in a retrieval method of the conventional retrieval device using hierarchical-structured keywords, the retrieval point becomes out of focus because the retrieval range is too wide. A user may fail to find a desired file quickly even when he/she refers to a list of retrieved files.